Careful Enough- An Adventure Time Story
by TaiylorWallace
Summary: Marshall Lee has always been reckless with his jokes and pranks, but what about when his 'bad little boy' ways hurt his best friend in the world? An Adventure Time Fionna & Marshall Lee story based on the super-epic cartoon by Pendleton Ward and the incredible gender-bent alternate universe within the story from the mind of the Ice King (and Marceline). -Taiylor Wallace


_**For Yei.**_

"Hey, girl, I'm goin' out with my man, you gonna be okay here on your own?" Cake called in from the kitchen as Lord Monochromicorn appeared outside the window.

"Yeah, I'll be fine. Marshall Lee's coming over," Fionna called back from where she lounged on the couch playing a game on BMO's screen.

"Ugh, haven't you had enough of that boy yet? All he does is make trouble." Cake poked her head out, a picnic basket in her paws.

"We're just gonna hang out, and maybe jam a little bit. I won't let him get into too much trouble." Fionna put down BMO's controller and stood up to stretch.

"Psh, he'll find a way. But I'll see you when I see you." Cake made her way out, hopping on Monochromicorn's back. Fionna watched them fly off before she went to get a drink from the kitchen. Before she knew what was happening, she was suddenly floating upside down hanging by her backpack.

"Whoa! Holy Glob!" She cried, and suddenly a familiar dark chuckle sounded above her. She looked up to see the half-demon Vampire King materialize out of thin air with his guitar on his back, holding Fionna off the ground with one hand. "Marshall!" She exclaimed, "put me down!"

Setting her down on her feet, Marshall smirked and lounged back, floating above her still. "Hey, Fionna."

"Do you always have to play pranks on me?"

"Uh. Yeah," he told her as if it was obvious before he pulled his guitar around to his chest and played a dark chord. "So, you ready for some sick tunes?"

"Let me get my flute!" Fionna smiled brightly and hurried to her room. Marshall Lee laughed aloud, somersaulting and following after her.

"A flute? Really? Only good little girls play flutes."

"And only good little boys play guitar," Fionna teased back as she stepped out with her flute in hand.

"Good little boys might play guitar, but I play an AXE guitar, girl."

"You try too hard." Fionna settled on the edge of the couch and began playing a sweet tune. Marshall Lee looked on with a smirk before he joined in with a few equally-sweet chords. The two traded songs back and forth for nearly an hour before Marshall Lee put his guitar down and sighed.

Fionna looked up with a quizzical expression. "What?"

"I'm outta music for now. Let's go do something cool."

"Okay, like what?"

"How about trick-or-treating?"

"Marshall, it's not Halloween. It's summer."

"Oh… then I guess if there's no candy, we gotta give 'em tricks." Marshall Lee smirked devilishly and disappeared out the open window, flying off toward the candy kingdom.

"Marshall!" Fionna called after him, and quickly hurried out of the treehouse after him. When she finally entered the gates after a long run, out of breath and panting heavily, she gasped to see Marshall Lee suddenly materialize in front of a candy corn woman, hissing at her. The woman screamed and fled, Marshall flying after her until Fionna tackled him to the ground.

"Hey! What the heck Fionna?" Marshall looked up at her as she landed on him. Fionna blushed as she realized the position they were in and Marshall smirked, "Oh, you just wanted to cuddle, huh?"

"No way!" Fionna quickly pulled away, but the moment she did, Marshall Lee was off after a candy cane man, picking him up and hanging him from a lamp post as the man cried out in distress.

"Stop it, Marshall!" Fionna quickly climbed up the post to help the man, carefully lowering him to the ground. Marshall was off again and he picked up a banana guard that was coming to see what the fuss was about, flying high in the air and dropping him. Fionna leapt from the lamp post and caught the screaming guard just before he splattered on the street. "Stop it!"

"Ha! You just don't get it, do you? You know this is what I do! This is who I am!" Marshall laughed maniacally, but Fionna jumped up and grabbed him by the leg. He flew up high onto the city wall. "Let go, man! You're jacking up my flight patterns!"

Fionna held on for dear life when she realized they were too high to survive a fall, until Marshall landed on one of the towers and she fell to her hands and knees. Jumping to her feet, she grabbed Marshall's sleeve before he could fly away. "Quit it, Marshall, you're gonna hurt someone!"

"Oh, come _on._ You know I won't when you're around to play little hero." Marshall Lee tried to pull away, but Fionna grabbed his arm. "Get off, man," Marshall pushed her away without realizing how close they were to the edge of the tower. Fionna stumbled back and her foot slipped off the edge.

"Mar-" _Riiiiiiip!_ His shirt sleeve tore from his arm, and Fionna disappeared over the edge.

"Fionna!" Marshall leapt over the edge, but he froze in midair at the sight below. "Oh… Glob…" He whispered as he looked down at Fionna with his sleeve still clutched in her hand. She'd fallen on a fence row between two homes and had broken through it, but Marshall could see the blood on the broken pieces. "No!" He cried out when his mind finally kicked back in after the shock of seeing his closest friend hurt. He raced down to her, gently turning her onto her back, and he lost his breath at the sight of a fence post's tip impaled in her belly. "Fi… Fionna… y-… you okay? Hey… come on, it's not funny. Answer me." He shook her gently and she moaned in pain but did not wake. "Come on, I promise I'll quit. No joke." But still, she lay motionless. Suddenly he was grabbed away from her and he hissed as he turned to see banana guards and candy people gathering.

"Get him! He hurt Fionna!" People called out and the crowd began to roar for his arrest, some even for execution.

"No! No, it was an accident!" Marshall Lee tried to explain, but the people simply roared louder and a few banana guards lobbed spears at him. He dodged them easily, but he couldn't evade all the candy cobble stones thrown at him by the angry mob. They surrounded Fionna and Marshall Lee was forced to flee. He flew away as fast as he could, but he paused near the gates, too high in the sky to be hit with any more rocks. He watched with a deep pain in his chest as the candy people carried Fionna into the castle. He suddenly realized he was crying, feeling the tears coursing down his cheeks. He didn't wipe them away, clenching his chest as the pain bloomed like fire. He flew away into the night and sought the darkest place he could find to hide and drown in his guilt.

For three days, he hid and worried like he'd never worried about anything before in his life. He didn't eat, he didn't sleep, and every time he tried to distract himself, he ended up playing sad songs on his guitar until he felt his eyes brim with tears. Then, he'd put the guitar down and sit with his knees drawn to his chest, internally yelling at himself for being so reckless and stupid and such a jerk. But on the third day, he finally came out as the sun sunk below the horizon. Watching as the moon rose among a few dark clouds, Marshall Lee finally made a decision. He made his way across the hills, pausing and nearly turning back several times, but eventually he arrived at the treehouse and took a glance through Fionna's bedroom window. Inside in the darkness, he could see Fionna lying in bed, obviously having a nightmare by how her face scrunched in fear in her sleep, and with the lights on in the kitchen below, he knew Cake wasn't there with her. Turning himself invisible, he slipped inside through the window silently. He heard Fionna whimper in her sleep and he came to her side, gently tucking her blanket around her.

Fionna awoke at a lance of pain in her belly when she shifted, and she lifted her head slowly, seeing the window open. She sat up painfully, cradling her stomach with one arm as a cold wind blew in and made her shiver. She tried to get up, but she felt an invisible hand stop her.

"I'll get it," Marshall Lee said softly as he materialized in front of her, and she gasped and pulled back fearfully. Marshall felt pain bloom in his chest again and his brows stitched together in worry. "I-it's okay, Fionna. I just came to see if you're okay." He gave her an unsure smile and tried to joke, "I wanted to see if there was a funeral, so I thought I'd stop by."

"Marshall Lee… get out." Fionna pulled herself further back on her bed.

"Don't be like that. Come on, it was just an acci-"

"Hey! Get your vampire butt away from my sister!" Cake suddenly shouted from the open doorway, charging in at Marshall Lee. He barely dodged the cat's tackle and flew up to the ceiling, trying to explain himself.

"It was an accident! I was just trying to have a little fun, and… and it got out of hand. I'm sorry, okay? Is that what you want? An apology?"

"Sayin' 'sorry' ain't gonna fix it this time!" Cake growled, earning a glare from the vampire.

"I'm not talking to you, you stupid cat, so just stay out of it!"

"Stop it!" Fionna suddenly cried, clenching her stomach at the pain as tears filled her eyes. Marshall Lee looked down at her and he felt his heart breaking at the fear and distrust in her eyes. "You always go too far, Marshall! You always hurt people, and you always pick on Cake! I told you before that I can take it if you're mean to me, but not other people. But… but this time, you went too far, even for me. You almost killed me. You're a reckless jerk and you always hurt me or my feelings somehow whenever we're anywhere near each other! This time you did both… and this time, I'm not ready to forgive you for it, and I'm sure not gonna shrug it off like I always did before!"

Marshall Lee stared at her in disbelief and pure heartbreak. All he wanted to do right then was hug her and promise he'd never hurt her again… but then he realized he'd always end up hurting her again, just like he always had. He couldn't help how his shoulders slumped and he couldn't even meet her eyes anymore. "I… I guess… I'll just go…"

"I guess you should," Fionna murmured, and watched with a heavy heart that was filled with guilt but also betrayal and fear as one of her dearest friends slipped out the window and into the night.

It was another week before Fionna was back on her feet, and yet another two before she was back to normal, coming out no worse for wear. After her first mission in almost a month from Prince Gumball, helping him build a new stone baking oven, Fionna had a moment alone while Cake was getting a sandwich from a food vendor to wander in the streets until she came upon the still-broken fence she'd fallen on. All the blood was cleaned up, but Marshall Lee's torn shirt sleeve was still there, soaked from the rain the night before. She picked it up and looked to the sky, thinking about what she'd said to him the night he'd visited her. He tried to cover up his true feelings with jokes all the time, but she knew he'd come to see her because he felt guilty and was genuinely scared she'd died of her wound. As bad as he tried to be, he had a good heart, and no one knew that better than she did.

"Hey, Fi, you comin' girl?" Cake called out.

"… No. I'm gonna go see Marshall Lee and make sure he's okay," Fionna told her friend, knowing she wouldn't be able to sneak away and do it.

"Are you crazy, kid? He almost killed you and you're still worryin' about him?" Cake fixed Fionna with a quizzical and worried stare. Fionna looked down at the torn plaid cloth in her hands and sighed quietly.

"I… I'm not sure I meant everything I said to him when he came to see me… he was so guilty, and he was so scared I'd died… I have to make sure he's okay. No one else has seen him since the candy people ran him off the night I got hurt."

"Hmm… okay, but if you ain't home by bedtime, I'm gonna kick that boy's buns and drag you home if I have to." Cake took a bite out of her sandwich.

"I'll be back by then, promise." Fionna nodded and turned to make her way out of the gates. She made her way to Marshall Lee's house in his cave, and immediately noticed how the place was ripped up and out of order, even more so than usual. The door wasn't even closed all the way. When Fionna peeked inside, she found the couch cushions torn up and the television left on with a fuzzy screen and all the lights left on too. Colorless apples were strewn everywhere, most of them beginning to rot. As she stepped in and called softly, "Marshall…?" she heard a thump from the bathroom. Quietly, she made her way to the door and pushed it open. Inside, she found Marshall Lee laying in the empty bathtub in his torn jeans and a gray long shirt. His hair was messier than ever and more apples and formerly red objects lay around the empty tub. His arm lay across his eyes and Fionna could see evidence of tear stains on his cheeks. She silently stepped up to the edge of the tub, still holding the torn sleeve in her hands.

"Marshall Lee?" She whispered, reaching out to touch his shoulder. The vampire's arm lifted from his eyes and when he saw her, he hissed and his eyes turned red before he suddenly flew up to the ceiling, planting his back and hands against it.

"The Glob are you doing here? Get out!" he snarled viciously, making Fionna take a step back in fear.

"Marshall, please, I just wanna talk."

"No! Get away! I'm just gonna hurt you again if you're near me!"

"I didn't mean that when I said it, I was just-"

"Just completely right. I'm a vampire and a half-demon, Fionna! I was born evil and I destroy everything I touch! And you know it!"

"No, you're not bad, Marshall, you're a good per-"

"Stop lying to yourself!"

"If you're not even a little bit good, then why are you my best friend?!" Fionna cried, making Marshall Lee pause. "I don't make friends with evil stuff! You might think you're a bad person for the stuff you did, but I know you're just a joker and sometimes you just don't know when it's too much and you don't know when to stop. That doesn't make you bad, it just makes you reckless and stubborn. And that's okay with me."

"How can I be 'okay' with you? I almost killed you!"

"But it was an accident. I know that, I always did. I was just angry and scared and hurting when you came to see me. I was the mean one… I'm sorry, Marshall."

"… Don't ever apologize for the truth." Marshall Lee disappeared from her sight, and she saw the door slam open and heard the front door do the same as her now-invisible friend flew off to wallow in his own guilt and self-hatred. She'd never seen him so hurt and so angry. Knowing she'd never find him until he wanted to be found, she quietly made her way about cleaning up all the discarded apples and setting his home to rights.

Before she left that night, she pinned a note to his door. It was midnight when Marshall Lee finally returned after he was sure Fionna was gone, and he slammed the door behind him as he entered with a growl at himself. He caught the slight sound of paper falling to the floor and he turned to see Fionna's note. Picking it up, he read over it with a confused stare.

_Marshall Lee,_

_I know you're angry and confused and hurt, but I want you to know that I forgive you for what happened, and I don't want to lose one of my best friends over an accident. So if you decide you feel the same, I'll be waiting for you after sunset on the hill in front of the treehouse whenever you're ready._

_-Fionna_

Immediately, Marshall Lee crumpled the note and tossed it aside with a growl. "She's crazy…" he muttered before retreating to his room and trying to focus on his guitar to distract himself all night. He hardly left until a week later when he realized he'd run out of food, so he begrudgingly went out just after the sun disappeared below the horizon to go pick apples in the forest. He knew he couldn't buy them after the candy people had run him out of town for hurting Fionna. He was so lost in his thoughts that he didn't realize he was passing the treehouse until he heard a familiar voice call his name.

"Marshall!" Fionna called from the hill, and Marshall Lee turned with a start. She was sitting at the top of the hill wrapped in a blanket, alone, and she looked… happy. Happy to see him. He began to back away, but as he did, Fionna's expression became sad, afraid he'd run away. Marshall realized he hated to see her sad, so he slowly drew closer until he was sitting in the grass beside her, but not too close.

"… How long have you been waiting for me to show up?" Marshall mumbled.

"Every night, til midnight," Fionna admitted and scooted closer to lace her arm through his own. He felt a blush heat his cheeks and he found that, though he was afraid to be close to her, he liked having her there, holding his arm so tightly.

"… You're stubborn."

"Not nearly as much as you are. I thought you'd never show up."

"I didn't really mean to. I kinda zoned out on my way to get food."

"Either way, I'm glad you're here. You know I can't hold a grudge against you, especially not over an accident. I missed you a lot, even when I was still hurting. I really could've used a good guitar ballad to help me feel better…" She laid her head against his shoulder, and smiled as he reached out with his free hand to lay over hers where it rested on his forearm.

"I'm sorta glad too… and if you'll take a rain check on that ballad, I bet I can make it up to you tomorrow."

"That sounds great to me."

"… Y'know, good little girls aren't supposed to forgive bad little boys."

"I must not be so good after all, or else you're not so bad."

"No, you were right with the first one. I think a jam session is just what we need, but I gotta be careful from now on. After all, you mortals are so fragile."

Fionna giggled and looked up to meet his dark eyes, feeling warmth in her chest at the sight of his welcome smile. She pressed a gentle kiss to his cheek, feeling both her own heat up with a blush. "Just try not to throw me off any more buildings and we'll call that careful enough."


End file.
